The invention relates to the refrigeration and, more particularly, to the continuous production of ice, mainly, water ice suspension in various solutions, for example, in various drinks, coolants in air conditioning systems, seawater, etc., using ice generators.
Various methods and devices for production of ice in solutions using ice generators are known (for example, U.S. Pat. Nos. 4,551,159, 4,936,114). Generally, by all these methods and devices it is possible to produce a sludge ice.
A disadvantage of sludge ice as a useful product is the difficulty of its delivery to the destination, because it needs the special transport and reloading facilities.
This disadvantage can be eliminated by the known method and device for continuous production of ice-solution suspension (liquid ice) using an ice generator (U.S. Pat. No. 5,383,342 of Ontec Ltd.), then the obtained suspension can be easily transported using conventional equipment (piping and pumps).
According to this method, the solution flow passes along a cooling element of ice generator to cool down the solution and form ice microcrystalls on the cooling surface of this element. The ice microcrystalls formed on the cooling surface are removed from this surface into the solution before any ice wall arises. The removed ice microcrystalls dispersed and dissipated uniformly throughout the entire volume of the solution flow thus form the ice suspension in the solution. This suspension leaves the ice generator as continues flow, which is suitable, as the Company advertised, for transport via conventional pipelines.
The device for accomplishment of this method is the ice generator, which has the channel for passing the solution. The cooling element that has the cooling surface intended for interaction with solution is located along the channel. The device contains means for removal of ice microcrystalls from the cooling surface of this element, which includes scrapers attached to the shalt mounted inside the channel.
However, the proposed method and device for its accomplishment have a number of drawbacks, namely:
Large quantities of ice microcrystalls in solution actively adhere to the ice generator internals (shaft, elements connecting scrapers to the shaft etc.) located near the channel axis, that causes negative mass-transfer balance of the formed ice microcrystalls. The mass-transfer balancexe2x80x94means the difference between the mass of ice removed from the processing zone in a unit of time and the mass of ice adhered to the internal elements in a unit of time. In applicant""s opinion, the said active adhesion caused by a relatively small flow turbulization in the zones near these internal elements. The said adhesion causes the keeping and accumulation of ice inside the channel until the channel is blocked up.
Periodical dysfunction of the regular microcrystalls removal from the cooling surface, since the ice wall arises on the cooling surface because of device process parameters fluctuations (increase of the initial solution temperature, local decrease of solution concentration, decrease of the refrigerant boiling point etc.) that causes the increase of the thermal resistance and, as a result, an additional loss of energy; and so this can fail the device.
Relatively low efficiency of utilization the heat flow transferred across the cooling element, since when the ice microcrystalls dispersed and dissipated uniformly throughout the entire volume of the solution flow, the most of them are away from the cooling surface. Consequently, the thermal resistance to the heat flow, which is being transferred during crystallization, considerably rises. In one""s turn, relatively low efficiency of the heat flow utilization requires increased specific energy consumption.
The object of this invention is to provide a method and a device for continuous production of ice-solution suspension using an ice generator, which could allow to arrange formation of ice microcrystalls in solution in such a manner, and provide such solution conditions, that the quantity of the ice microcrystalls adhered on the ice generator internals will be significantly decreased providing the positive balance of the formed ice microcrystalls mass transfer and prevent the ice wall formation on the cooling surface and thus reduce energy loss and exclude the possibility of the device operation failure.
The set problem is solved by the following way: the solution, continuously fed to the processing zone, is overcooled; then the turbulization is performed in the overcooled solution; as a result, ice microcrystalls are formed in the solution; after that the formed ice-solution suspension is removed from the processing zone; by this, the said turbulization is chosen with such intensity that the formed ice microcrystalls mass transfer balance will be positive, considering their adhesion on the internal surfaces in processing zone.
The set problem is also solved by the way that the device for implementation of this method is the ice generator which has a channel having an inlet for solution feed and an outlet for ice-solution suspension evacuation, and it also includes a cooling element having a cooling surface intended for interaction with solution. The device also includes means for removal of the formed overcooled solution from the area of its direct thermal contact with the cooling surface, and means for solution turbulization.